internal.aka-ns.net has no MX records.
Question and response
Question
dig internal.aka-ns.net. MX
Answer
The response has no answer records.
Authority
aka-ns.net. 9000 SOA internal.aka-ns.net. hostmaster.akamai.com. 1727371830 90000 90000 90000 180
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0